The joints of lower extremities are often in need of repair through surgical procedures. Quite common among these are hip and knee replacements, although surgery on the ankle is also quite common. Following such surgeries, there is necessarily a period of therapy and rehabilitation, where the repaired joint is mobilized or flexed during the healing process in order to ensure that the joint has recovered properly and provides the patient or individual with as close to a full range of mobility as possible.
In the past, patients would typically engage therapy sessions, during which a therapist would mobilize and manipulate the affected joint while the patient remained otherwise immobile. There is, of course, pain associated with such mobilization and manipulation, and patients are often apprehensive of such treatment and urge against the mobilization efforts of the therapist during treatment. To a large extent, the treatment is out of the control of the patient, giving rise to the apprehension and repelling patient reaction.
Previous devices for lower extremity therapy through mobilization have typically functioned in an open chain manner, creating a sliding motion of the tibia around the femur. This is contrary to the natural flexion of the knee, and the same is generally true with the hip and ankle. Such machines and their use are counterproductive to effective therapy and rehabilitation.